Ice Sheet Disintegration

Ice sheet change is expected to be a "slow" climate feedback. How rapidly ice sheets can
disintegrate is one of the most uncertain and imporant climate issues. The dominant physical
process causing ice sheet disintegration may be absorption of heat by the ocean (due to an
increasing greenhouse effect), resulting melting of ice shelves, and thus an increased rate of
discharge of ice from the ice sheet to the ocean. Once this process gets well underway, it may be difficult to
prevent accelerating ice sheet disintegration under its own impetus (
http://pubs.iss.nasa.gov/docs/2005/2005_Hansen.pdf).

Also in PDF

Also in PDF. (last modified 2017/08/02)

The figure above shows the rate of mass loss from the Greenland and Antarctic ice sheets, based on updates of Rignot et al. (2011) and Velicogna et al. (2014), and NASA Global Climate Change: Vital Signs of th Planet web page (Data through January 22, 2017).
The rate of mass loss from Greenland has increased during the past several years,
as it has from Antarctica. This is one of the most important
geophysical measurements being made, so it is important to get a follow-on gravity satellite into
space. A planned European gravity satellite is not sufficiently capable to yield accurate ice sheet
mass change, and a planned NASA follow-on gravity mission is low on NASA's priority list.